How to isolate interference from edge computing box industrial frequency converters?

Industrial frequency converters generate strong electromagnetic interference through pulse width modulation, which is conducted and coupled to the edge computing box, causing communication interruptions. Isolation measures include:

1. A three-phase filter is connected in series at the power input; if single-phase, two stages of common-mode inductors (CML4532A-101T and CML3225A-510T) are cascaded to suppress broadband interference.

2. Signal lines use fiber optic converters or isolated RS485 modules with a withstand voltage of 2.5kV.

3. Copper braided tape is used for equipotential bonding (<0.1Ω) between the edge box chassis and the frequency converter cabinet.

4. For analog inputs (4-20mA), add signal isolators and pre-install a 2.2nF/2kV Y capacitor for PE discharge.

In a test of a certain project, communication between the frequency converter and the edge box was normal 5 meters away. After implementing the above isolation scheme, the bit error rate decreased from 35% to 0.01%.